/*


*   v-dialogDrag 指令

*/
import {
  isPC
} from '@/utils'

function dialogDrag(el, binding, vnode, oldVnode) {
  let _this = this;
  //弹框可拉伸最小宽高
  let dialogTables = null;
  let minWidth = 820;

  let minHeight = 420;

  //初始非全屏

  let isFullScreen = false;

  //当前宽高

  let nowWidth = 0;

  let nowHight = 0;

  //当前顶部高度

  let nowMarginTop = 0;

  //获取弹框头部（这部分可双击全屏）

  const dialogHeaderEl = el.querySelector('.el-dialog__header');

  //弹窗

  const dragDom = el.querySelector('.el-dialog');

  //限制窗口

  dragDom.style.overflow = "hidden";

  if (!isPC()) {
    dragDom.style.width = '90%'
  }

  //头部加上可拖动cursor

  dialogHeaderEl.style.cursor = 'move';

  // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
  const sty = (function () {
    if (window.document.currentStyle) {
      return (dom, attr) => dom.currentStyle[attr];
    } else {
      return (dom, attr) => getComputedStyle(dom, null)[attr];
    }
  })();
  //拖拽边界优化
  let moveDown = (e) => {
    // 鼠标按下，计算当前元素距离可视区的距离
    const disX = e.clientX - dialogHeaderEl.offsetLeft;
    const disY = e.clientY - dialogHeaderEl.offsetTop;
    const screenWidth = document.body.clientWidth; // body当前宽度
    const screenHeight = document.documentElement.clientHeight; // 可见区域高度(应为body高度，可某些环境下无法获取)
    const dragDomWidth = dragDom.offsetWidth; // 对话框宽度
    const dragDomheight = dragDom.offsetHeight; // 对话框高度
    const minDragDomLeft = dragDom.offsetLeft;
    const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;
    const minDragDomTop = dragDom.offsetTop;
    const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight;
    // 获取到的值带px 正则匹配替换
    let styL = sty(dragDom, 'left');
    let styT = sty(dragDom, 'top');
    // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
    if (styL.includes('%')) {
      // eslint-disable-next-line no-useless-escape
      styL = +document.body.clientWidth * (+styL.replace(/\%/g, '') / 100);
      // eslint-disable-next-line no-useless-escape
      styT = +document.body.clientHeight * (+styT.replace(/\%/g, '') / 100);
    } else {
      styL = +styL.replace(/\px/g, '');
      styT = +styT.replace(/\px/g, '');
    }

    document.onmousemove = function (e) {
      // 通过事件委托，计算移动的距离
      let left = e.clientX - disX;
      let top = e.clientY - disY;

      // 边界处理
      if (-left > minDragDomLeft) {
        left = -minDragDomLeft;
      } else if (left > maxDragDomLeft) {
        left = maxDragDomLeft;
      }
      if (-top > minDragDomTop) {
        top = -minDragDomTop;
      } else if (top > maxDragDomTop) {
        top = maxDragDomTop;
      }

      // 移动当前元素
      dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`;
    };

    document.onmouseup = function (e) {
      document.onmousemove = null;
      document.onmouseup = null;
    };
    return false;
  };

  dialogHeaderEl.onmousedown = moveDown;

  //双击头部全屏效果

  dialogHeaderEl.ondblclick = (e) => {

    if (isFullScreen == false) {

      nowHight = dragDom.clientHeight;

      nowWidth = dragDom.clientWidth;

      nowMarginTop = dragDom.style.marginTop;

      dragDom.style.left = 0;

      dragDom.style.top = 0;

      dragDom.style.height = "100VH";

      dragDom.style.width = "100VW";

      dragDom.style.marginTop = 0;

      isFullScreen = true;

      dialogHeaderEl.style.cursor = 'initial';

      dialogHeaderEl.onmousedown = null;

    } else {

      dragDom.style.height = "auto";

      dragDom.style.width = nowWidth + 'px';

      dragDom.style.marginTop = nowMarginTop;

      isFullScreen = false;

      dialogHeaderEl.style.cursor = 'move';

      dialogHeaderEl.onmousedown = moveDown;

    }

  }
}
export default {
  bind(el, binding, vnode, oldVnode) {
    dialogDrag(el, binding, vnode, oldVnode)
  }
}
